From: Tom Lane <tgl@sss.pgh.pa.us>
To: Melanie Plageman <melanieplageman@gmail.com>
cc: Robert Haas <robertmhaas@gmail.com>, Peter Geoghegan <pg@bowt.ie>,
        Heikki Linnakangas <hlinnaka@iki.fi>,
        Pg Hackers <pgsql-hackers@postgresql.org>,
        Andres Freund <andres@anarazel.de>, Noah Misch <noah@leadboat.com>
Subject: Re: Vacuum ERRORs out considering freezing dead tuples from before
 OldestXmin
In-reply-to: 
 <CAAKRu_YurMWLu+iYLW7ky8Lc_88HyhWt0RmBRmq2zPCjP8QtuA@mail.gmail.com>
References: 
 <CAAKRu_bDD7oq9ZwB2OJqub5BovMG6UjEYsoK2LVttadjEqyRGg@mail.gmail.com>
 <CAH2-WzkZUDr8TQDPuax1SmJg9B5yz-Qhr7NdoQJD5PpXLAUA7Q@mail.gmail.com>
 <acbce1b9-e88e-4a33-9fa7-4728f67454f2@iki.fi>
 <CAAKRu_apNU2MPBK96V+bXjTq0RiZ-=A4ZTaysakpx9jxbq1dbQ@mail.gmail.com>
 <CAAKRu_Z4PybtZ0i_NKOr-vbrFW5p1ZdfEfUqaeU8fLPhszpP_g@mail.gmail.com>
 <CAH2-WzmXqaX37VCVjTDBF5cauzUgXOkuXsSTLOq56EAB1vzkeQ@mail.gmail.com>
 <CAAKRu_b49z=TSUZG+i0NCEPW409wqsb3Y4MCaMRBVC6ZWKBeVw@mail.gmail.com>
 <CAAKRu_bQFifK3U=VGKpR5MXLaCWHZ-jf0N6xJvMnf_XYB2OR9A@mail.gmail.com>
 <CAH2-WznnDZgZAOUins9ye8_=Y=892N2mvjs9bUB8s37gXnOKQQ@mail.gmail.com>
 <CAAKRu_b+9i71Kk4MB3SxFMzox84En=v+X31sFvRzJ-ZsXVi0qw@mail.gmail.com>
 <614152.1721580711@sss.pgh.pa.us>
 <CAH2-Wz=3TJ86JF_Puv7zThOxZKAVyiNZED_4bxGEdRyftGY5Vg@mail.gmail.com>
 <729493.1721595882@sss.pgh.pa.us>
 <CAAKRu_ZZrbQrYaGrMHG1YTUfP=p88sJ0YSXdFMzYX61MNQJ9gg@mail.gmail.com>
 <889997.1721663290@sss.pgh.pa.us>
 <CA+TgmobN+5uDPdwyPJqTWdvvJqXqztB26C=RxyTRVXmuxaKkcw@mail.gmail.com> <!
 CAAKRu_YurMWLu+iYLW7ky8Lc_88HyhWt0RmBRmq2zPCjP8QtuA@mail.gmail.com>
Comments: In-reply-to Melanie Plageman <melanieplageman@gmail.com>
	message dated "Mon, 22 Jul 2024 14:17:46 -0400"
MIME-Version: 1.0
Content-Type: text/plain; charset="us-ascii"
Content-ID: <932344.1721687794.1@sss.pgh.pa.us>
Date: Mon, 22 Jul 2024 18:36:34 -0400
Message-ID: <932345.1721687794@sss.pgh.pa.us>
Archived-At: 
 <https://www.postgresql.org/message-id/932345.1721687794%40sss.pgh.pa.us>
Precedence: bulk

Melanie Plageman <melanieplageman@gmail.com> writes:
> We've only run tests with this commit on some of the back branches for
> some of these animals. Of those, I don't see any failures so far. So,
> it seems the test instability is just related to trying to get
> multiple passes of index vacuuming reliably with TIDStore.

> AFAICT, all the 32bit machine failures are timeouts waiting for the
> standby to catch up (mamba, gull, merswine). Unfortunately, the
> failures on copperhead (a 64 bit machine) are because we don't
> actually succeed in triggering a second vacuum pass. This would not be
> fixed by a longer timeout.

Ouch.  This seems to me to raise the importance of getting a better
way to test multiple-index-vacuum-passes.  Peter argued upthread
that we don't need a better way, but I don't see how that argument
holds water if copperhead was not reaching it despite being 64-bit.
(Did you figure out exactly why it doesn't reach the code?)

> Because of this, I'm inclined to revert the test on 17 and master to
> avoid distracting folks committing other work and seeing those animals
> go red.

Agreed as a short-term measure.

			regards, tom lane